Amino acid residues in the pro region of Escherichia coli heat-stable enterotoxin I that affect efficiency of translocation across the inner membrane

Escherichia coli heat-stable enterotoxin Ip (STIp), which is a typical extracellular toxin consisting of 18 amino acid residues, is synthesized as a precursor consisting of pre (amino acid residues 1 to 19), pro (amino acid residues 20 to 54), and mature (amino acid residues 55 to 72) regions. Though the pre region functions as a conventional leader peptide that guides the following region to cross the inner membrane, the role of the pro region in the maturation pathway remains to be elucidated. We previously indicated that the sequence from residues 29 to 38 in the pro region increases the efficiency of STI translocation across the inner membrane (H. Yamanaka, Y. Fuke, S. Hitotsubashi, Y. Fujii, and K. Okamoto, Microbiol. Immunol. 37:195-205, 1993). We therefore examined the amino acid residues in the sequence that are responsible for this function. We substituted several amino acid residues in the sequence by means of oligonucleotide-directed site-specific mutagenesis. We then evaluated the effect of the substitution on the efficiency of STI translocation across the inner membrane by determining the enterotoxic activity of the culture supernatant, the amount of a fusion protein consisting of STI and nuclease A released into the periplasm, and the amount of the labeled ST released into the periplasm after pulse-labeling with [35S]cysteine. Substitution of the charged amino acid residues at positions 29 to 31 (K-E-K) with hydrophobic (I-V-L, F-W-F, or F-W-Q) or basic (K-K-K) residues significantly reduced these values in every assay. In contrast, the substitution of these amino acid residues with acidic amino acid residues (E-E-E) increased these values in all assays. This means that the negative charge near position 30 is important for STI to translocate efficiently across the inner membrane. A similar substitution of lysine residues at positions 37 and 38 showed that they are not involved in the translocation of STI across the inner membrane.

Different biodistribution of 99mTc-labelled chimeric mouse-human monoclonal antibody between athymic mice model and human

Biodistribution of chimeric mouse/human monoclonal antibody against non-specific cross-reacting antigen (chNCA Ab) was studied in athymic mice and patients with metastatic bone disease. 99mTc-chNCA Ab showed a high labelling efficiency, stability and also a high binding ratio to human granulocytes. Since NCA showed cross-reactivity with carcinoembryonic antigen (CEA), animal experiments showed that 99mTc-chNCA Ab was accumulated in the xenografted tumour which expressed CEA, suggesting the preserved immunoreactivity of labelled materials. In the clinical study, injected 99mTc-chNCA Ab formed a high molecular weight complex immediately after intravenous administration and was trapped mainly in liver. The first-phase plasma half-life was 6.4 +/- 1.1 min. None of the patients showed adverse reaction or human antimurine or anti-chimeric antibody in their serum. 99mTc-chNCA Ab demonstrated remarkably different biodistribution between patients and the animal model and showed different pharmacokinetics from other murine and chimeric Abs reported previously. For safety HPLC analysis should be performed before clinical radioimmunodetection or radioimmunotherapy by incubating radiolabelled MAb with human serum under strict conditions.

Interaction between the intracellular Ca2+ stores in rat dissociated hippocampal neurones

The interaction between the Ca(2+)-activated K+ currents (IK(Ca)) induced by acetylcholine (ACh), 1-aminocyclopentane-1S,3R-dicarboxylic acid (1S,3R)-ACPD) and caffeine in rat hippocampal CA1 neurones was investigated to examine the functional independence between IP3- and Ca(2+)-sensitive Ca2+ stores. Pretreatment with either ACh or (1S,3R)-ACPD almost completely suppressed the subsequent IK(Ca) induced by another. Pretreatment with caffeine partially suppressed the IK(Ca) induced by either ACh or (1S,3R)-ACPD, although the inhibitory effect varied among the neurones, while pretreatment with either ACh or (1S,3R)-ACPD also partially inhibited the caffeine-induced IK(Ca). Continuous treatment with ryanodine and thapsigargin nonselectively decreased both the caffeine- and ACh-induced IK(Ca). These results thus indicate a close interaction between IP3- and Ca(2+)-sensitive stores and also suggest that the relative size of both stores and the closeness between them differ among neurones.

Effect of aromatase inhibitor, TZA-2209, on the prostate of androstenedione-treated castrated dogs: changes in prostate volume and histopathological findings

To determine whether the inhibition of estrogen-related effect in the prostate would be of value in the management of benign prostate hyperplasia (BPH), we examined the effect of TZA-2209, a new steroidal aromatase inhibitor, on the prostate in three of six castrated beagles that received 75 mg/week androstenedione. The three other animals served as controls. Sequential measurements of prostate volume by transrectal ultrasonography showed that the volume in TZA-treated dogs was significantly decreased compared with that in the controls. Prostatic aromatase activity was suppressed by TZA administration. Histopathologically, the stromal component was increased and glands were atrophied by androstenedione treatment. TZA administration increased the volume of the glands. Immunohistochemical detection of estramustine-binding protein showed more positive staining of the protein in the glands that were increased in volume by TZA administration. We concluded that the aromatase inhibitor effectively antagonized the estrogen-related stromal changes, however, this action was accompanied by stimulation of the glandular component due to the accumulation of androgens, the substrate of the aromatase. In the light of these findings, we suggest the simultaneous treatment for the androgen-glandular component route in the prostate is necessary for the effective management of BPH.

Significantly increased frequency of the apolipoprotein E epsilon 4 allele in elderly non-demented leprosy patients

Apolipoprotein E (apo E) genotypes in 350 leprosy patients were examined and compared with those of 870 age-matched controls. The allelic frequencies of the apo E gene did not differ between demented patients with leprosy and controls. However, the frequency of apo E epsilon 4 allele was significantly higher in non-demented leprosy patients than in controls (P < 0.001). Of special interest is that the prevalence of E3/4 genotype in non-demented leprosy patients increased significantly with age, being 14.1%, 24.4%, and 28.3% in the 60s, 70s, and 80s, respectively (P < 0.05). These data suggest that apo E epsilon 4 is not a risk factor for senile dementia in elderly leprosy patients, and there exist factors to overcome the risk of apo E4 in leprosy patients.

Divergent effects of methotrexate on the clonal growth of T and B lymphocytes and synovial adherent cells from patients with rheumatoid arthritis

OBJECTIVE

To define the mechanisms whereby methotrexate (MTX) manifests its effects in patients with rheumatoid arthritis.

METHODS

T and B cells from peripheral blood and rheumatoid synovial tissues, synovial adherent cells, and the human fibrosarcoma cell line HT1080 and its mutant (defective in an enzyme in the nucleotide salvage pathway) were tested for clonal growth when cultured with MTX. Normal human fibroblasts and those with a deficiency in a salvage pathway were cultured with MTX in the presence or absence of purine and pyrimidine bases.

RESULTS

Clonal growth of T and B cells, but not synovial cells, was inhibited by clinically relevant concentrations of MTX. Slowly proliferating fibroblast lines were resistant to MTX, whereas their rapidly proliferating counterparts were not. However, mutant fibroblast lines deficient in a salvage pathway were sensitive to MTX despite slow proliferation. Similarly, while skin fibroblasts were resistant to MTX, germline mutant fibroblasts deficient in a salvage pathway were sensitive to small concentrations of MTX.

CONCLUSION

T and B lymphocytes, but not synovial cells, may be the target of MTX in vivo. Resistance to MTX may be associated with slow proliferation and the ability to synthesise nucleotides via salvage pathways. MTX can inhibit proliferation of even slowly growing cells by restricting the supply of nucleotides obtained via a salvage pathway, by removal of purine and pyrimidine bases, or by inducing a deficiency in a salvage pathway. It may be possible to manipulate the therapeutic effect of MTX by adjusting the amounts of purines and pyrimidines available to the cells in vivo.

[Etiology of prostate cancer and significance of screening for early prostate cancer]

The incidence and mortality rate of prostate cancer in Japan are lower than in Western countries. Though studies of migrating populations would suggest that dietary or environmental factors may influence the etiology of the disease. The Westernized lifestyle after the Second World War may have influenced the increasing incidence of this disease in Japan. The screening by prostate specific antigen (PSA) on an asymptomatic healthy population can detect early prostate cancer. It is expected that the mortality may be decreased through such a system. However, some scientists hesitate to perform an aggressive program of early detection because of the possibility of latent cancer detection, the difficulty of distinguishing between clinically important and unimportant cancer, a high false positive rate to detect early stage cancer, and the lack of well-executed randomized prospective studies. Current clinical studies of the prostate cancer have demonstrated that the unimportant cancer detection rate by PSA was less than 10%. When a 4.0 ng/ml PSA cut-off value is applied for early detection, the false positive rate is approximately 80%. It is important to make subjects examined by the screening program aware of its the meaning. However, there is not a complete and cost-effective diagnostic modality to detect early prostate cancer. Moreover, it is confirmed that radical prostatectomy improves survival, but it has not been confirmed to improve the mortality based on population. We propose that well-executed randomized studies by the end point of the survival, cancer death rate, cost effective, QOL and etc. are urgently needed.

Correlation analysis between bladder cancer and cigarette smoking in various countries

Cigarette smoking is considered to be a risk factor of bladder cancer. We investigated the relationship between bladder cancer mortality rates and cigarette smoking prevalence in various countries, and examined whether only the difference of smoking prevalence could explain the difference of mortality rates of bladder cancer in each country or not. The age-adjusted mortality rates from bladder cancer were high in European countries and low in Asian countries. The sex ratios ranged between 2 to 6 in most of the countries. For 20 countries, the mortality rate from bladder cancer was not correlated with the cigarette smoking prevalence. However, when the analysis was restricted to 16 countries in Europe, North America and Oceania (Caucasians), the correlation coefficients between them were high, being 0.68 (p < 0.01) in males and 0.49 (0.05 < p < 0.1) in females. In both Japan and the United States, cigarette smoking prevalence declined while the incidence of bladder cancer increased in males, both being stable in females. Race might be considered to be a strong risk factor of bladder cancer, followed by the prevalence of cigarette smoking. It is necessary to follow the changes of incidence rates of bladder cancer in the future to evaluate the influence of cigarette smoking.

Granulosa cell tumor arising in the ovary irradiated 22 years earlier for endometrial stromal sarcoma

We encountered a rare case of metachronous tumors in a 57-year-old Japanese housewife who presented with an ovarian granulosa cell tumor 22 years after receiving treatment for endometrial stromal sarcoma. Treatment consisted of a total abdominal hysterectomy and left salpingo-oophorectomy followed by 40 Gy whole abdominal irradiation. Since the second tumor occurred in the ovary that had been previously irradiated to treat the first metachtonous neoplasm, the present case can help to improve our understanding of the histogenesis of granulosa cell tumors.

Acute renal failure in a patient with chronic glomerulonephritis after the administration of luteinizing hormone-releasing hormone analogue given for rectal obstruction due to prostate cancer

We report a case in which rectal obstruction due to prostate cancer was exacerbated due to an ileus after the administration of luteinizing hormone-releasing hormone analogue. The obstruction to led to copious vomiting, dehydration and renal failure which necessitated hemodialysis. Improvement of the patient was noted four weeks after the start of hormonal treatment with a decrease in rectal obstruction concomitant with decreases in testosterone and prostate specific antigen levels.

[The estrogen-induced changes of estrogen receptor in seminal vesicle of immature castrated rat]

We have already reported that estrogen treatment given to immature castrated rats caused proliferative changes in both collagen and smooth muscle in the seminal vesicles of immature rats detected by light microscopy. Herein, we studied the estrogen-induced changes in estrogen receptor (ER) in the seminal vesicles of immature castrated rats by means of enzyme immunoassay, an immunohistochemical method and RT-PCR, to clarify the mechanism of estrogen induced proliferation of collagen and smooth muscle. Immature rats (3 weeks old) were castrated and left untreated for 3 weeks and then injected subcutaneously with estradiol-17 beta (E2-17 beta, 5 micrograms/day) for 7 days before they were killed. The nuclear ER content per gland, mg tissue and mg protein in the seminal vesicles of castrated rats increased markedly compared with those of non-treated rats. Castration also enhanced ERmRNA expression. The immunohistochemical analysis demonstrated the obvious tissue distribution by which the nuclear ER positive cells were densely distributed in the periglandular stroma. The nuclear ER contents per gland, mg tissue and mg protein in the seminal vesicles of estrogen-treated castrated rats were greater than those in castrated rats. Estrogen treatment further enhanced ERmRNA expression in the castrated rats. The immunohistochemical studies demonstrated that the nuclear ER positive cells appeared among the glandular epithelial cells, basal cells and the peripheral stromal cells, in addition to the periglandular stromal cells. These findings suggest that ER is related to the estrogen induced proliferation of collagen and smooth muscle in the seminal vesicles of immature castrated rats.

Transurethral balloon laser thermotherapy: effects of a directionally shielded balloon in canine prostates

BACKGROUND

Transurethral balloon laser thermotherapy (TUBAL-T) improves objective, but not subjective, symptoms of benign prostatic hyperplasia (BPH). We studied whether or not an Nd:YAG laser beam with a shielded balloon could successfully irradiate the prostate during TUBAL-T in selective manner, to improve the subjective symptoms.

METHODS

TUBAL-T was performed on canine prostates using the balloon with a laser probe, which was shielded anteriorly at 90 degrees (from the center of the balloon) and posteriorly at 90 degrees.

RESULTS

At 20 watts laser power, the relative power density in the bilateral non-shielded areas was 17.4 and 17.8, and in the shielded area it was 1.0. Observation by thermography revealed that the temperature after laser radiation in a non-shielded area of a fish cake phantom was higher than in a shielded area. Following transurethral thermotherapy using a shielded balloon in dogs, a cavity was formed bilaterally around the urethra, and the tissues at the anteroposterior sides and the urethra were preserved.

CONCLUSIONS

TUBAL-T, which has been performed in clinical cases of benign prostatic hyperplasia, might be useful in selective irradiation of adenoma if a shielded balloon is used.

Effects of a new steroidal antiandrogen, TZP-4238 (17 alpha-acetoxy-6-chloro-2-oxa-4, 6-pregnadiene-3, 20-dione), on spontaneously developed canine benign prostatic hyperplasia

The effects of the new steroidal antiandrogen, TZP-4238 on spontaneously-developed canine prostatic hyperplasia (BPH) were studied in comparison with those of chlormadinone acetate (CMA), a steroidal antiandrogen used for the treatment of BPH and prostatic cancer in Japan. Aged beagle dogs (5-9 years old) with spontaneously developed BPH (mean prostate volume, 17.7ml) were treated orally with a placebo, TZP-4238 (0.1 mg/kg/day, 0.01 mg/kg/day), or CMA (3 mg/kg/day), for 25 weeks. Prostate volume was measured by transrectal ultrasonography before treatment and every 5 weeks during treatment. TZP-4238 produced a regression in spontaneously developed canine BPH, its effects being more potent than those of CMA. TZP-4238 reduced the content of testosterone, dihydrotestosterone (DHT) and androgen receptor in the prostates of these animals, suggesting antiandrogenic mechanisms of the agent. TZP-4238 also appeared to reduce 5 alpha-reductase activity by prevention of the androgen action in prostate as described above.

Production of monoclonal antibody against the C1 component of rat estramustine-binding protein: immunohistochemical study of rat prostate

The monoclonal antibody against estramustine-binding protein (EMBP) was produced by immunizing a mouse with EMBP antigen purified from rat ventral prostate. On western blotting analysis this antibody recognized the EMBP C1 component, and in an absorption test it recognized the EMBP antigen. Immunohistochemically, this antibody revealed positive staining for the ventral and dorsolateral prostate. In the epithelium of the ventral prostate, intense immunostaining was observed in the intraluminal secretory product; however, in the epithelium of the dorsolateral prostate, the staining was intense in the cytoplasm of the epithelial cells. These findings suggested differences of EMBP localization in the ventral and the dorsolateral prostate. Since the intensity of immunostaining for EMBP was decreased in the prostate of castrated rats, we considered that this antibody reflected the androgen dependency of EMBP.

[Epidemiological study of risk factors for bladder cancer]

A case-control study was conducted on 303 male bladder cancer patients and controls. General population controls were chosen from 15 areas in Gunma Prefecture and were matched by age (+/- l y.o.) to the subjects. Age-adjusted and smoking-adjusted odds ratio (O.R.) and a 95% confidence interval (C.I.) were calculated for each item. Risk factors for bladder cancer in men were investigated. The O.R. tended to be significantly higher for those who had history of smoking, who smoked more per day, who had smoked longer, whose Brinkman index was higher, who began smoking younger and who inhaled deeper than it was for non-smokers. O.R.s of having a past history or complication of cystitis (age-adjusted) and benign prostatic hypertrophy (age- and smoking-adjusted) were significantly higher, but the difference was supposed to be caused by bias. There was a significantly lower age- and smoking-adjusted O.R. for bladder cancer in men who engaged in sales, whose blood type was O, who drank milk frequently, who ate grains frequently, who age vegetables frequently and who had a past history or complication of hypertension. The number of cases and controls with first degree family members who developed cancer respectively supposed to be highly related to smoking, were as follows; 16 and 8 for lung cancer, 3 and 0 for larynx cancer and 6 and 3 for bladder cancer. The following characteristics failed to show any significant difference between subjects with bladder cancer and the control group; height and weight now and 20 years ago, jobs which deal with dye, academic career, marriage, number of children, alcohol drinking and the use of hair dye or analgesics.

Resistibility to Theileria sergenti infection in Holstein and Japanese Black cattle

To clarify the resistibility against Theileria sergenti infection in Holstein and Japanese Black cattle under controlled conditions in artificial environmental chambers, those breeds of calves were infected with T. sergenti by infestation with the same number of infected ticks. No apparent differences between the two breeds were observed in the feeding numbers and feeding periods of ticks infested. The level and duration of parasitemia were clearly less and shorter in Japanese Black than those in Holstein calves. With progress of parasitemia, packed cell volume (PCV) and erythrocyte number decreased in both breeds. However, the minimum PCV and erythrocyte number recorded in Japanese Black were higher than those in Holstein calves. These results suggest that the Japanese Black shows solider resistance to T. sergenti infection than the Holstein breed does under experimentally controlled condition without external factors.

Selection against blood cells deficient in hypoxanthine phosphoribosyltransferase (HPRT) in Lesch-Nyhan heterozygotes occurs at the level of multipotent stem cells

Lesch-Nyhan syndrome is caused by a severe genetic deficiency of hypoxanthine phosphoribosyltransferase (HPRT) and is characterized by central nervous system disorders, gout, and in some cases, macrocytic anemia. Women heterozygous for HPRT deficiency are healthy but their somatic cells are mosaic for enzyme deficiency owing to random inactivation of the X chromosome. Frequencies of red blood cells and T cells deficient in HPRT are significantly lower than the expected 50% in heterozygotes, suggesting that HPRT-negative blood cells are selected against in heterozygotes. To determine at which stage of hematopoiesis such selection occurs, we determined the frequencies of HPRT-negative T, B and erythroid precursor cells in three heterozygotes. Since the cloning efficiencies of T and B cells and colony forming efficiency of burst-forming unit erythroid (BFU-E) for sample from Lesch-Nyhan patients were similar to those of normal cells, HPRT deficiency does not seem to render the differentiated cells less efficient for proliferation. However, the frequencies of HPRT-negative T and B cells, and BFU-E were all less than 10% in each of the three heterozygotes. Although the frequencies of HPRT-negative cells showed tenfold variations between the heterozygotes, each heterozygote had similar frequencies of HPRT-negative cells in the three cell types. These results suggest that HPRT is important at early stages of hematopoiesis, but less so after the cells have differentiated into T cells, B cells and erythroid precursor cells.

Adenine phosphoribosyltransferase deficiency identified by urinary sediment analysis: cellular and molecular confirmation

Adenine phosphoribosyltransferase deficiency is an autosomal recessive purine enzyme defect that causes urolithiasis and, in severe cases, renal failure. Most homozygotes with this disorder were identified by analyses of excreted or surgically removed urinary stones, but some were identified only because they were family members of symptomatic individuals. We report here the detection of adenine phosphoribosyltransferase deficiency in two cases by routine analysis of urinary sediments. 2,8-Dihydroxyadenine-like spherical crystals were observed in the urinary sediment, and a diagnosis of homozygous adenine phosphoribosyltransferase deficiency was confirmed by cellular and molecular methods. A molecular diagnostic system using the polymerase-chain reaction and single-strand conformational polymorphism analysis proved to be a rapid and sensitive method to identify the APRT*J allele, a common mutant allele among the Japanese people. These methods will facilitate identification of symptomatic and asymptomatic individuals with homozygous adenine phosphoribosyltransferase deficiency.